Heathrow is paving the way for a wider shake-up of airline security checks by introducing privacy-friendly bodyscanners that replace graphic images of the human torso with a cartoon-like picture. The changes could mean the end of metal detectors and full body searches.

Britain's largest airport has launched a trial using millimetre-wave scanners that bounce radio waves, instead of x-ray beams, off a passenger's body. Travellers who set off metal detectors in Terminal 4 will be taken to the passenger-screening area, where they will be allowed to look at the scanner's image with security officers. If there is a suspicious package on the person, it will show up as a yellow box on a mannequin-like representation of the passenger's body.

"It will be effective security and a much better passenger experience," said Ian Hutcheson, director of security at BAA, which owns Heathrow. Under previous trials at Heathrow and other UK airports, graphic images of passengers' bodies are viewed by security officials in an enclosed area. BAA plans to use the new scanners in all its airports if the trial is successful.

Hutcheson said bodyscanners could ultimately replace metal detectors as the main technology for screening passengers, amid UK and European Union reviews of airport security rules. "If the machine could cope with the totality of the throughput [of passengers] we could dispense with metal detectors," said Hutcheson, adding that there will be far fewer pat-down searches as a consequence.

Bodyscanners were tried in the UK after Umar Farouk Abdulmutallab, a Nigerian student, nearly brought down Northwest Airlines flight 253 to Detroit on Christmas Day 2009 when he set off an explosive device in his underwear. However, Manchester airport, which uses scanners that deploy low-level x-ray beams, said millimeter-wave scanners were less efficient.

"We looked at millimetre wave but don't believe that it is sufficiently developed for operational use," said a Manchester Airport spokesman. "For example, it cannot penetrate wet clothes, so if it rains – and we are in Manchester, after all – coats would have to be removed."

Hutcheson added that bodyscanners could be put into widespread use as part of a new airport security regime that will subject passengers to different levels of security checks. The US Transportation Security Administration is developing a programme that would favour low-risk travellers if they supply advance information such as frequent-flyer details and travel records, allowing them to pass through security areas more quickly. "They are grasping the concept that not every passenger presents the same level of risk and is different to other passengers," said Hutcheson.

BAA has already introduced a new level of security at Heathrow by training staff in behavioural detection. Under the new technique, staff have been trained by government agencies to detect suspicious or anomalous behaviour by travellers in terminals. If staff remain concerned after questioning them, those passengers are then referred to immigration officers or police.

Hutcheson said bodyscanners, behavioural detection and basing security checks on risk rather than random selection helped introduce unpredictability into a security process that demands all passengers are subject to the same amount of screening.

"If you don't know exactly what level of screening is going to be applied at the airport, then you introduce a level of unpredictability that makes it harder for terrorists to plan attacks," he said.

A Department for Transport spokesperson said: "We are currently consulting on changes to the way security is regulated. Our proposals would give airport operators more freedom to introduce more efficient and passenger-friendly processes while still delivering the same high levels of security. Subject to the outcome of this consultation and continuing discussions in Europe, these changes could see increased use of new technology in delivering aviation security."

• This article was amended on 5 September 2011. The original said the new scanners "bounce electromagnetic waves, instead of x-ray beams, off a passenger's body". To clarify: the new scanners use radio waves. Both radio waves and x-rays are on the electromagnetic spectrum, however radio waves are of a much lower frequency than x-rays, and are harmless.